Tag Archives: Design

Though I haven’t written much in the past year, I’ve been logging away thoughts (engineering, and otherwise). One in particular kept resonating with me last summer when looking over some road designs: how can you design a road for all vehicles without having driven them?

Designers rarely refer to books alone, but utilize experiences that back up the numbers. You’d be hard pressed to find a transportation engineer in the United States that has never driven a car; it’s the most prominent personal transportation method here. But you might more easily find transportation engineers that have never driven a motorcycle. Or an FHWA Class 8, four-axled truck and trailer. Yet we design roads daily, sometimes with the use of simulations, sometimes with nothing more than a reference guide and our engineering judgement. But there’s a disconnect there. Last October, I aimed to remedy one part of this problem and have some fun doing it: learn how to ride a motorcycle.

The MSF Course

I highly recommend the MSF Beginner Rider Course. In three days they have you prepped to pass the DMV rider test, without having ever ridden a motorcycle. Kim and I took the course together for fun and we had a blast. Click here to find a course near you.

Road Design

Lets look at a standard road curve. While many characteristics of road design have remained for years, roadway curves changed drastically with the invention of the automobile. Super-elevated roads, for example, were inspired by cant railways, where the two rails are designed at different elevations to accommodate a “banked turn”. As a road designer, it’s easy to check the Green Book to find super-elevation guidelines, but they mean so much more with a bit of experience behind the wheel; anyone who has driven a vehicle faster than 30 miles an hour can recognize the importance of a banked turn. Superelevation can be even more important to motorcycle riders. Leaning on a motorcycle is a fantastic way to appreciate how banked turns work to your advantage and the turns reinforce the importance of getting your spirals, runoff, and runout lengths correct.

Road designers also immediately appreciate other successes and deficiencies of road design while riding a motorcycle. Adequate drainage for sheet flow during a storm, stopping and decision sight distances, pavement cross slopes, the condition of the pavement, and locations of road debris accumulation all become much more apparent. The affect of ANY road condition that could develop into a traffic safety hazard magnifies a hundred-fold, as do the consequences of a collision. Experiencing these road conditions on two wheels can be both humbling and horrifying.

For those more interested in the physics side there is a whole subject on the mechanics of bicycle and motorcycles which explains leaning and counter-steering at high speeds. These, along with the center of gravity of the bike, can be used to calculate the maximum degree of lean possible.

Closing

Credit is rarely placed on the experiences many take for granted, so designers and engineers should always be looking for new experiences that share insight into their designs. I highly recommend the experience I’ve had, and I’ll be looking into a class on semis in the future. Perhaps a bit of time behind the wheel of a semi will lead to a better understanding of maneuverability on roads designed without trucks in mind. I encourage other road designers to do the same.

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Mike Roselli, PE

Mike Roselli is a Civil Engineer and consultant, licensed in the States of NC, SC, GA, and FL, and is focused on providing land development services to clients building in the Triangle Area. He currently resides in Cary, NC.